Vehicle seat with a seat height adjustment device

ABSTRACT

A locking device for a vehicle seat with a seat frame and a seat height adjustment device has two guide links fixed to the body, with a swivel support on a horizontal axis. The guide links can swivel in different angular positions for adjusting the height of the seat. One guide link has a geared unit for swiveling it, while both the guide links are connected to each other by means of a connecting rod so that they do not rotate with respect to each other. A locking device with an inertia-sensitive element works on the side opposite to that of the geared unit between seat frame and adjacent guide link. A spring working on the inertia-sensitive element keeps the locking device in the normally unlocked position. The inertia-sensitive element is a locking element for latching with an interlocking element. The locking element is under a pre-load by the spring, which moves it, while in the state released from its contact with the locking element, into a interlocking position with the guide link which fixes the guide link so that it does not rotate once the inertia sensing element senses inertia.

TECHNICAL FIELD

[0001] The invention concerns a vehicle seat and in particular, a vehicle seat including an inertia-sensitive element that is designed as a locking element.

BACKGROUND INFORMATION

[0002] In a vehicle seat as generally known (DE 198 41 197 A1), a spring pre-loads an inertia-sensitive element positioned on the gear side which in the event of a crash, sets a guide link. In a crash the force of inertia of the element overcomes the spring load. The guide link remains set, if the inertia exceeds the spring load. If the spring load becomes greater again, the locking is released.

[0003] During accidents, several impacts can follow each other in quick succession, whether because the vehicle skids along out of control after an accident or because one after another, several vehicles drive into each other. In such cases, the known locking devices do not help ascertain whether the locking device released after the first impact still works and whether it responds again to the subsequent impact.

[0004] Based on this state of the art, the task underlying the invention is to create a vehicle seat with a seat height adjustment device of an already known type, where the locking ability is retained after the first release.

SUMMARY OF THE INVENTION

[0005] In the proposed locking device, the seat height adjustment is blocked, until it is unlocked after the release process. Since different springs charge the interlocking element and the locking element, their dimensions can be different. The interlocking process therefore takes place very quickly due to the higher spring load, even though the release force is moderate.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] These and other features and advantages of the present invention will be better understood by reading the following detailed description, taken together with the drawings wherein:

[0007]FIG. 1: A side view of a seat frame with a locking device for a seat height adjustment device according to the present invention;

[0008]FIG. 2: A magnified view of the locking device from FIG. 1 in the unlocked condition; and

[0009]FIG. 3: A view of the locking device similar to FIG. 2, in locked condition.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The drawings show only a seat frame 1 for the vehicle seat, which connects to the longitudinal adjustment rails 2, with height adjustment by means of two parallel front and rear guide links 4, 5 respectively. The backrest supported on a locking swivel of the seat frame 1 has not been shown. The figure only shows a front guide link 4 and rear guide link 5 on the side of the seat frame 1, on which a belt lock 8 of the safety seat belt has also been fitted. The fitting (not shown) for the height adjustment with a drive unit for swiveling the rear guide link is located on the opposite side of the seat frame 1. The non-swiveling, maneuverable guide link (not shown) on the opposite side of seat frame 1 is connected with the guide link 5 parallel to it by means of connecting rod 6 rotating about an axis 3.

[0011] The guide link operated for adjusting the height is set at the selected height. In the event of a crash, a high force passes through the belt lock 8 to the side of the seat frame 1 connected with the seat belt. This force is transmitted through the connecting rod 6 to the guide link 5 fixed through the drive unit, often with unacceptable deformation. Therefore a locking device 7, activated in the event of a crash, is provided for guide link 5.

[0012] The locking device 7 features an inertia-sensitive locking element 7 a and an interlocking element 7 c. The inertia sensitive locking element 7 a and the interlocking element 7 c are levers, which are supported about axes 7 f and 7 g respectively, which are parallel to each other and parallel to axis 3, swiveling on the seat frame 1. The locking element 7 a has a surface 7 h, FIG. 2, which latches on behind surface 7 i on the interlocking element 7 c. A spring 7 b keeps surface 7 h in contact with surface 7 i. The interlocking element 7 c has a ratchet-like saw-tooth formation 7 e, and sits opposite the concentric to the axis 3 ratchet-like saw-tooth formation 5 a on guide link 5 for every swivel position of the guide link. A spring 7 b keeps the interlocking element 7 c from engaging with the guide link 5. Spring 7 d keeps the interlocking element 7 c pre-loaded and facing the counter-gearing and disengaged from the saw tooth formation 5 a of guide link 5.

[0013] In the event of a crash, the locking element 7 a swivels in the clockwise direction about the axis 7 f due to the force of inertia, as FIG. 3 shows. The surface 7 h disengages from surface 7 i and releases the interlocking element 7 c. The spring 7 d swivels and pulls the interlocking element 7 c about the axis 7 g. The saw tooth formation 7 e grips into and engages with the counter gearing saw tooth formation 5 a. The spring 7 d maintains the tooth grip (tension) on the gearing 7 e and counter-gearing 5 a, even if the force of inertia has dwindled. The interlocking can be disengaged only by manually resetting the interlocking element 7 c and the locking element 7 a until the latching is disengaged.

[0014] Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present invention which is not to be limited except by the claims which follow. 

The invention claimed is:
 1. A locking device for a vehicle seat with a seat frame and a seat height adjustment device having two guide links swiveling on axes, said seat height adjustment device fixed to the vehicle and swiveling into different angular settings to adjust the height of the seat, with a single gear unit for the swiveling of the guide links, both guide links connected to each other without relative rotation by means of a connecting rod, said locking device located on a side of said seat opposite to the drive unit, on one of said guide link adjacent said locking device having an inertia-sensitive element, wherein a spring acts on the inertia-sensitive element keeping the locking device in the unlocked condition, said locking device comprising: wherein said inertia-sensitive element is designed as a locking element to be engaged with an interlocking element which is under a pre-load by a spring which moves the interlocking element from engagement with the locking element into a locked position with said one of said two guide links when said inertia sensitive element senses inertia which causes said inertia sensitive element to rotate and disengage from said interlocking element, wherein the one guide link is set and unable to rotate.
 2. A locking device according to the claim 1 wherein the interlocking element includes a ratchet-like gearing for engaging with a corresponding ratchet like gearing disposed on said adjacent guide link.
 3. A locking device according to claim 1 characterized in that the interlocking element and the locking element are designed as levers supported on the seat frame and swivel about parallel axes.
 4. A locking device according claim 2 characterized in that the interlocking element and the locking element have surfaces designed for mutual latching and engagement.
 5. A locking device according to claim 2 characterized in that the ratchet like gearing on said guide link is designed as a curved saw tooth arrangement arranged on one edge of the guide link which is made from a flat material.
 6. A locking device according to claims 5 characterized in that the curved saw tooth arrangement traces a path about the axis of the one guide link with a generally constant radius.
 7. A locking device according to claim 1 characterized in that the interlocking element and said one guide link include interlocking meshing teeth designed in a saw-tooth form. 